Re: Remove xmin and cmin from frozen tuples

People:

> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Considering the cost/benefits, rather than doing some optimization for
> > long-lived tuples, I would like to see us merge the existing
> > xmin/xmax/cmin/cmax values back into three storage fields like we had
> > in 7.4 and had to expand to a full four in 8.0 to support
> > subtransactions.

Hmmm. I personally don't see a whole lot of value in trimming 4 bytes per
row off an archive table, particularly if the table would need to go
through some kind of I/O intensive operation to do it.

Where I do see value is in enabling index-only access for "frozen" tables.
That would be a *huge* gain, especially with bitmaps. I think we've
discussed this before,though.

--
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco